Asma Saeed, et al. “β-GALACTOSIDASE FROM WATERMELON (Citrullus Lanatus) SEEDLINGS: PARTIAL PURIFICATION AND PROPERTIES”. Pakistan Journal of Biotechnology, vol. 14, no. 3, Aug. 2017, pp. 271-8, https://pjbt.org/index.php/pjbt/article/view/522.